Tornadoes and Climate Change

McKibben is wrong; many reporters are “making connections”

On Monday, The Washington Post published an op-ed by Bill McKibben, a writer and environmental activist, under the sarcastic headline, “A link between climate change and Joplin tornadoes? Never!”

McKibben mockingly chastises… well, the world, apparently. He directs his accusatory screed at “you” (as in, not him) for taking a hear-no-evil-see-no-evil position when it comes to potential connections between extreme weather and manmade climate change:

Caution: It is vitally important not to make connections. When you see pictures of rubble like this week’s shots from Joplin, Mo., you should not wonder: Is this somehow related to the tornado outbreak three weeks ago in Tuscaloosa, Ala., or the enormous outbreak a couple of weeks before that (which, together, comprised the most active April for tornadoes in U.S. history). No, that doesn’t mean a thing…

It’s far smarter to repeat to yourself the comforting mantra that no single weather event can ever be directly tied to climate change.

When it comes to the media, at least, McKibben is off his rocker. Many journalists, at news outlets large and small, are asking questions about tornado-climate connections. They’re just not making the kind of overwrought assertions he seems to expect. In fact, they’re doing a fairly good job explaining the relationship between tornadoes and climate change, just as they did during the Russian heat wave and Pakistani floods last summer. Evidence abounds that journalists are getting better at covering the nuances involved in the relationships between climate change and various types of extreme weather.

Even Climate Progress’s Joseph Romm, a fierce critic who routinely flogs reporters for not explaining the threat of climate change more assertively, was fairly complimentary in a nice roundup; he even wrote that, “Today weatherman Al Roker appears to have gone beyond the data with his suggestion that “climate change” is bringing tornadoes to urban areas, although, admittedly, it is a brief clip and it’s not exactly clear what he is saying.” (Romm compliments McKibben’s op-ed, but they’re brothers-in-activism where climate is concerned, and well within their rights to express their opinions about the need to act.)

So what are the data and scientists saying? Let’s go back to coverage of the tornadoes that tore through the southeast and south in mid- to late April (see this 2011 tornado information fact sheet for details). Andrew Freedman quickly kicked out pieces for The Washington Post and Climate Central describing the immediate meteorological conditions (involving a southerly position of the of the jet stream and warm sea surface temperatures in the Gulf of Mexico, which abetted the convergence of a hot, humid air mass close to the ground and a cold, dry one higher up, which got all twisted up and formed funnel clouds—see this primer from the National Severe Storm Laboratory)—that created the tornadoes. He also dutifully explored the climate connection, explaining that, contrary to McKibben’s assertion in the Post:

Those of us who write about climate change are often accused of attempting to link every unusual weather event to climate change, as if increasing air and ocean temperatures can explain everything from hurricanes to snowstorms. In this case, with the second-deadliest tornado outbreak in US history, and with the most tornadoes for any April since records began in the early 1950s, it’s important to understand that the scientific evidence indicates that climate change probably played a very small role, if any, in stirring up this violent weather. This might disappoint some advocates who are already using this to highlight the risks of climate change-related extreme weather.

A few days later, Wonkroom’s Brad Johnson (a colleague of Romm’s at the Center for American Progress) shook things up when he published interviews with three eminent climatologists. The most assertive statements came from Kevin Trenberth, head of the Climate Analysis Section of the National Center for Atmospheric Research, and Michael Mann, director of the Earth System Science Center at Pennsylvania State University. They told him, respectively, that “It is irresponsible not to mention climate change. … The environment in which all of these storms and the tornadoes are occurring has changed from human influences (global warming),” and “Climate change is present in every single meteorological event, in that these events are occurring within a baseline atmospheric environment that has shifted in favor of more intense weather events.”

The third, and most complete, quote came from Gavin Schmidt, a climate modeler at the Goddard Institute for Space Studies, who said:

It is a truism to say that everything has been affected by climate change so far and therefore this latest outbreak must in some sense have been affected, but attribution is hard, and the further down the chain the causality is supposed to go, the harder this is. For heat waves it is easier, for statistics on precipitation intensity it is easier — there are multiple levels of good modeling, theory, and observations to back it up. But we have much less to go on with tornadoes.

Andrew Revkin put it a little more bluntly at his New York Times Dot Earth blog:

There’s no doubt that Michael Mann of Pennsylvania State University is right when he says “climate change is present in every single meteorological event” — in the sense that the buildup of greenhouses gases is a background nudge everywhere.

But that’s a meaningless assertion without asking whether there is evidence of a meaningful influence — meaning enough of a nudge to the atmosphere that the contribution from greenhouse gases is relevant to policy and personal choices, in this case in tornado zones.

Most major news outlets have done a good, stressing the immediate meteorological causes of the tornadoes and the high level of uncertainty surrounding their relation to climate change. Take the Q&A-style explainers published May 25 in the The New York Times and Los Angeles Times on pages sixteen and seventeen of the papers’ A sections, respectively. Take wire services like the Associated Press and Agence France-Presse, or magazines like Time. Take regional outlets like The Christian Science Monitor, the Houston Chronicle, the Kansas City Star, the Toledo Blade in Ohio, and the Anniston Star in Alabama. Take specialty publications like ClimateWire,, and New Scientist.

One could pick nits with all of these pieces, but they faithfully and carefully convey the message of a preliminary report on April’s tornadoes from the National Oceanic and Atmospheric Administration’s (NOAA) Climate Attribution Rapid Response Team:

A change in the mean climate properties that are believed to be particularly relevant to major destructive tornado events has thus not been detected for April, at least during the last 30 years. So far, we have not been able to link any of the major causes of the tornado outbreak to global warming. Barring a detection of change, a claim of attribution (to human impacts) is thus problematic, although it does not exclude that a future change in such environmental conditions may occur as anthropogenic greenhouse gas forcing increases.

Some pieces didn’t display enough skepticism. A USA Today post, titled “Climate change could spawn more tornadoes,” is one example. It cited studies in Proceedings of the National Academy of Sciences and Geophysical Research Letters to support the headline’s assertion. Those papers focused on severe thunderstorms, which can create tornadoes and are likely to be more frequent in a warming world, but they didn’t actually say much about twisters themselves (which are not inevitable byproducts of severe thunderstorms).

After it was published in 2007, the author of the paper in Geophysical Research Letters, Anthony Del Genio, told the AP’s Seth Borenstein that “The strongest thunderstorms, the strongest severe storms and tornadoes are likely to happen more often and be stronger.” But last year he told the Toledo Blade’s Tom Henry that, “while scientists are convinced the status quo will result in more violent weather years from now, tornadoes are ‘really beyond the edge of our understanding of things.’” In 2008, a paper in Transactions of the American Geophysical Union emphasized that the relationship between tornadoes and climate change remained “mostly unexplored.” So did one in 2009 in Geophysical Research Letters.

Describing “the existing state of knowledge on climate change and tornadoes,” NOAA’s Climate Attribution Rapid Response Team cited the Intergovernmental Panel on Climate Change and the U.S. Climate Change Science Program, both of which agree that there is insufficient evidence to determine trends in the frequency and intensity of small-scale weather events like tornadoes. Indeed, there is a lot of evidence tempering USA Today’s declaration that “Climate change could spawn more tornadoes,” but its post mentioned none of it.

At any rate, McKibben’s contention that no one is “making connections” or asking questions about twisters and warming is completely unfounded. On May 5, NOAA’s own ClimateWatch Magazine reported, “These days, when the weather breaks records, it’s natural to wonder if global warming is to blame. So it’s not surprising that in recent weeks, climate scientists have been fielding lots of questions about the possible connection between global warming and tornadoes.”

If anything, the connections that most journalists are failing to make are the ones to the immediate steps that can be taken to improve tornado preparedness and reduce vulnerability. Revkin has made this argument repeatedly at his New York Times Dot Earth blog, writing on May 23 that:

It’s fine for Kevin Trenberth of the National Center for Atmospheric Research to say he feels “it is irresponsible not to mention climate change” when discussing tornado outbreaks. Everyone’s entitled to his or her view.

My response would be that it is irresponsible not to mention the need to reduce inherent and avoidable human vulnerability to tornadoes in the crowding South, particularly in low-income regions with flimsy housing. I saw barely a mention of these realities in recent posts by climate-oriented bloggers on the tornado outbreak.

Indeed, reports like one from The Christian Science Monitor’s Patrick Johnson, which explored the contradiction between improved storm-monitoring technology and the startling death toll this season, have been rare. On May 23, Johnson reported that:

On average, tornado deaths in the United States have gone from 8 per 1 million people in 1925 to 0.11 per 1 million people today - a trend largely attributed to early-warning systems fed by advanced meteorology and the introduction of Doppler radar.

Yet the stunning death tolls from tornadoes this spring raise new questions about government subsidies for storm shelters, the psychology of warning response, the possibility of limited tornado evacuations, and the argument that tornado warning and response should be considered a national security issue.

A Reuters article stressed the importance of enacting stronger building codes and building tornado “safe rooms,” and The New York Times reported that a record number of people are indeed now “scrambling to install shelters.” (ABC News had an interesting piece quoting an engineer and an architect explaining why safe rooms are better investments than trying to “tornado-proof” a whole home, which is “probably not worth the expense.”)

Revkin highlighted a lack of basements in tornado-prone regions, and cited a 2008 study by Ashley Walker, a meteorologist at Northern Illinois University, which found that 44 percent of deaths in tornadoes occur in mobile homes (a figure Walker says is now up to 50 percent). “In the tornado zone, the focus, going forward, should remain on improving responsiveness to warnings, construction standards and the availability of shelter,” Revkin argued in another post.

Reducing the greenhouse-gas emissions that contribute to climate change should also be a priority, of course, but on the list of things that can be done to protect people from tornadoes, it barely registers. And while it’s fine to ask questions about connections between climate change and twisters, journalists have a responsibility to the public, and there are more important connections to make.

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Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard. Tags: , , , ,